Method and apparatus for calibrating thermometers

ABSTRACT

A calibration device allows accurate and consistent creation of ice baths and aids in the calibration of food safety thermometers. Such devices include a calibration wrench on a cup lid for holding and calibrating a thermometer, a stem thermometer access hole on the cup lid, an insulated cup for holding a substance to be measured, and a liquid crystal reversible temperature label on the cup.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. provisional patent application No. 61/417,610, filed Nov. 29, 2010, the contents of which are herein incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to measurement and calibration equipment and, more particularly, to a device that accurately measures the temperature of an ice bath and aids in the exact calibration of individual food safety thermometers.

The U.S. Department of Agriculture (USDA) requires daily calibration of food safety thermometers. The ice bath calibration method is popular in most food outlets because it is relatively easy to perform. A user may place ice in a bowl and rest pocket test thermometers in the ice. They then read the temperatures of each thermometer. However, it is nearly impossible for two people to create an identical ice bath. Since most food service outlets do not measure the temperature of the bath first, accurate calibration is virtually impossible.

As can be seen, there is a need for an apparatus and method for repeatable creation of a properly constructed ice bath and an almost immediate and accurate temperature reading.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are top views of two embodiments of a calibration device according to exemplary embodiments of the present invention;

FIGS. 1C and 1D are side views of the two embodiments of FIGS. 1A and 1B, respectively;

FIGS. 1E and 1F are perspective views of the two embodiments of FIGS. 1A and 1B, respectively;

FIG. 2A is a top view of the calibration device of FIG. 1A or 1B;

FIG. 2B is a top cross-sectional view of the calibration device of FIG. 2A;

FIG. 2C is a side view of the calibration device of FIG. 2A;

FIG. 2D is a side cross-sectional view of the calibration device of FIG. 2A;

FIG. 2E is a perspective view of the calibration device of FIG. 2A;

FIG. 3A is a top view of a lid of the calibration device of FIG. 1A;

FIG. 3B is a top view of a lid of the calibration device of FIG. 1B;

FIG. 3C is a cross-sectional view of the lid of FIG. 3A;

FIG. 3D is a cross-sectional view of the lid of FIG. 3B;

FIG. 3E is a close-up view of a calibration wrench of the lid of either FIG. 3A or FIG. 3B;

FIG. 4A is a top view of an alternate embodiment of a lid for a calibration device;

FIG. 4B is a bottom view of the lid of FIG. 4A;

FIG. 4C is a cross-sectional view taken along line C-C of FIG. 4A;

FIG. 4D is a side view of the lid of FIG. 4A; and

FIG. 4E is a close-up view taken about section B of FIG. 4D.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

Broadly, an embodiment of the present invention provides a device that allows accurate and consistent creation of ice baths and aids in the calibration of food safety thermometers. Devices according to embodiments of the present invention include a calibration wrench on a cup lid for holding and calibrating a thermometer, a stem thermometer access hole on the cup lid, an insulated cup for holding a substance to be measured, and a liquid crystal reversible temperature label on the cup.

Referring now to FIGS. 1A, 1C and 1E, a calibrating device 30 may have a lid 11 assembled to a cup 17. The lid 11 may have a calibration wrench 13 on a side thereof. The calibration wrench 13 may be configured to engage a calibration adjuster or nut of a stem thermometer when the thermometer (not shown) is inserted in an access hole 16 centrally disposed within the calibration wrench 13. The calibration wrench 13 may be raised or recessed with respect to a surface of lid 11. The calibration wrench 13 may properly position a stem thermometer in calibrating device 30 and may prevent the stem thermometer from contacting an inner surface of an interior of cup 17 when assembled thereto. The access hole 16 may be formed or machine through the lid 11 and may allow a user to assemble or insert the stem thermometer into calibrating device 30.

The lid 11 may have a raised lip 15 formed about a perimeter thereof, which may be configured to allow the lid 11 to engage with cup 17 and may create an interference fit therewith.

Referring to FIGS. 1B, 1D and 1F, a calibrating device 40 may be similar to the calibrating device 30, described above, and may include a lid 12 assembled to the cup 17. The lid 12 may have the calibration wrench 13 and a second calibration wrench 14 formed or machined on a side thereof. The calibration wrenches 13 and 14 may be formed in the same size to allow the calibrating device 40 to receive two thermometers having the same size stem nut. In some embodiments, the calibration wrenches 13 and 14 may be formed in different sizes to allow the calibrating device 40 to receive two thermometers having different sized stem nuts.

Referring now to FIGS. 2A-2E, the cup 17 may have an inner vessel 18. The inner vessel 18 may be configured to fit inside the cup 17. The inner vessel 18 and the cup 17 may have a space or gap 23 therebetween and may be joined with a seal 22. The seal 22 may be a welded joint or seal that may rigidly join the cup 17 with the inner vessel 18. The inner vessel 18 may have a liquid crystal temperature label 19 affixed thereon. The label 19 may be affixed to the inner surface of the inner vessel 18, and may be visible or legible by a user from an outside of the cup 17. For example, the cup 17 and the inner vessel 18 may be made of a clear or transparent material to permit the user to see the label 19. A dotted line (see FIG. 2D) may be disposed to provide an ice fill level indicator.

In an exemplary embodiment of the present invention, the calibration wrench 13 may be configured to engage a No. 10 hexagonal nut (or, in some embodiments, an 8 mm nut). The calibration wrench 14 may be configured to engage a No. 12 hexagonal nut (or, in some embodiments, a 10 mm nut). The access hole 16 may be located about the center of the calibration wrench 13, 14, and may be from about 1 to about 5 mm in diameter, typically about 3 mm in diameter. The raised lip 15 may be from about 1 mm to about 5 mm thick, typically about 2 mm, thick. The cup 17 may be made of a clear polycarbonate plastic and may be from about 2 mm to about 3 mm thick. The inner vessel 18 may be a clear polycarbonate plastic and may be from about 0.025 inch to about 0.05 inch thick. The seal 22 may be a sonically welded joint, for example. The gap 23 may be filled with air, an inert gas, or may be a vacuum or near-vacuum. The calibration device 30, 40 may have instructions of use affixed or printed thereon as a label, or as embossed, raised or etched lettering. The inner vessel 18 may be configured to hole about 16 to about 20 fluid ounces.

FIGS. 3C and 3D show cross sectional views of the lids 11 and 12 of FIGS. 3A and 3B respectively, and illustrate an embodiment where the calibration wrenches 12 and 13 are recessed into a surface of the lids 11 and 12. FIG. 3E is a detail plan view of a portion marked as section A-A on FIG. 3A, and illustrates a portion of the calibration wrench 13. The portion of calibration wrench 13 illustrated may be generally a chevron shape having an angle 24 of about 120 degrees and configured to engage a calibration adjustor of a stem thermometer. It should be noted that the specific dimensions referred to in FIGS. 3A-3E are exemplary dimensions. Other dimensions of various components are within the scope of the present invention.

Referring now to FIG. 4A-4E, a lid 50 according to another embodiment of the present invention is shown. The lid 50 may have a first calibration wrench 51 on a first side thereof and a second calibration wrench 52 on a second side thereof. The calibration wrenches 51, 52 may have an access hole 53 therewithin, which may permit insertion of a stem thermometer therethrough. The lid 50 may have a raised lip 54 located about a perimeter of the first side thereof, and a raised lip 54 located about a perimeter of the second side thereof. The raised lips 54 may be configured to allow the lid 50 to engage with the cup 17, and may create an interference fit therewith. The access hole 53 and the calibration wrenches 51, 52 may be configured coaxially or concentrically. The calibration wrenches 51, 52 may be configured to engage or receive similar or dissimilar stem thermometers.

It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. 

1. A cup comprising: a cup body; a lid fitting on the cup body, the lid having one or more calibration wrenches, the calibration wrenches each including at least one protrusion or recess, the at least one protrusion or recess adapted to contain a nut of a thermometer; and an access hole formed through the lid at a location of each of the one or more calibration wrenches.
 2. The cup of claim 1, wherein the one or more calibration wrenches includes a first angled member disposed opposite a second angled member, the first and second angled members adapted to retain the nut of the thermometer.
 3. The cup of claim 1, wherein the one or more calibration wrenches includes a first hexagonal recess.
 4. The cup of claim 3, wherein the one or more calibration wrenches includes a second hexagonal recess, wherein the first hexagonal recess is formed on a first side of the lid and the second hexagonal recess is formed on a second side of the lid, coaxial with the first hexagonal recess.
 5. The cup of claim 1, further comprising an inner vessel fitting inside the cup body.
 6. The cup of claim 5, wherein the inner vessel is sealed to the cup body with a gap formed therebetween.
 7. The cup of claim 6, wherein the gap includes an insulating material.
 8. A cup comprising: an exterior cup body; an inner vessel disposed inside the exterior cup body; a lid adapted to fit about a perimeter of the exterior cup body; one or more calibration wrenches disposed in the lid, the calibration wrenches each including at least one protrusion or recess, the at least one protrusion or recess adapted to contain a nut of a thermometer; and an access hole formed through the lid at a central location of each of the one or more calibration wrenches.
 9. The cup of claim 8, wherein the one or more calibration wrenches includes a first angled member disposed opposite a second angled member, the first and second angled members adapted to retain the nut of the thermometer.
 10. The cup of claim 8, wherein the one or more calibration wrenches includes a first hexagonal recess and a second hexagonal recess, wherein the first hexagonal recess is formed on a first side of the lid and the second hexagonal recess is formed on a second side of the lid, coaxial with the first hexagonal recess. 